Remove MIPS architecture

The MIPS architecture port has been added 5+ years ago in order to
support a Chrome OS project that ended up going nowhere. No other board
has used it since and nobody is still willing or has the expertise and
hardware to maintain it. We have decided that it has become too much of
a mainenance burden and the chance of anyone ever reviving it seems too
slim at this point. This patch eliminates all MIPS code and
MIPS-specific hacks.

Change-Id: I5e49451cd055bbab0a15dcae5f53e0172e6e2ebe
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34919
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

payloads/libpayload/drivers/timer/img_pistachio.c

@@ -1,38 +0,0 @@
-/*
- * This file is part of the libpayload project.
- *
- * Copyright (C) 2014 Imagination Technologies
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
-#include <libpayload.h>
-#include <arch/cpu.h>
-
-uint64_t timer_hz(void)
-{
-	return (uint64_t)lib_sysinfo.cpu_khz * 1000;
-}
-
-uint64_t timer_raw_value(void)
-{
-	static uint64_t total_ticks = 0;
-	uint8_t overflow = 0;
-	uint32_t current_ticks = read_c0_count() * 2;
-
-	/* It assumes only one overflow happened since the last call */
-	if (current_ticks <= (uint32_t)total_ticks)
-		overflow = 1;
-	/* The least significant part(32 bits) of total_ticks will always
-	 * become equal to current ticks */
-	total_ticks = (((total_ticks  >> 32) + overflow) << 32) +
-				current_ticks;
-	return total_ticks;
-}